blkfront: fixes for 'xm block-detach ... --force'
Prevent prematurely freeing 'struct blkfront_info' instances (when the xenbus data structures are gone, but the Linux ones are still needed). Prevent adding a disk with the same (major, minor) [and hence the same name and sysfs entries, which leads to oopses] when the previous instance wasn't fully de-allocated yet. This still doesn't address all issues resulting from forced detach: I/O submitted after the detach still blocks forever, likely preventing subsequent un-mounting from completing. It's not clear to me (not knowing much about the block layer) how this can be avoided. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
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203fd61f42
Коммит
0e34582699
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@ -105,6 +105,10 @@ struct blkfront_info
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static DEFINE_SPINLOCK(blkif_io_lock);
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static unsigned int nr_minors;
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static unsigned long *minors;
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static DEFINE_SPINLOCK(minor_lock);
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#define MAXIMUM_OUTSTANDING_BLOCK_REQS \
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(BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
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#define GRANT_INVALID_REF 0
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@ -139,6 +143,55 @@ static void add_id_to_freelist(struct blkfront_info *info,
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info->shadow_free = id;
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}
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static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
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{
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unsigned int end = minor + nr;
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int rc;
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if (end > nr_minors) {
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unsigned long *bitmap, *old;
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bitmap = kzalloc(BITS_TO_LONGS(end) * sizeof(*bitmap),
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GFP_KERNEL);
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if (bitmap == NULL)
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return -ENOMEM;
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spin_lock(&minor_lock);
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if (end > nr_minors) {
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old = minors;
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memcpy(bitmap, minors,
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BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
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minors = bitmap;
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nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
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} else
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old = bitmap;
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spin_unlock(&minor_lock);
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kfree(old);
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}
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spin_lock(&minor_lock);
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if (find_next_bit(minors, end, minor) >= end) {
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for (; minor < end; ++minor)
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__set_bit(minor, minors);
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rc = 0;
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} else
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rc = -EBUSY;
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spin_unlock(&minor_lock);
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return rc;
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}
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static void xlbd_release_minors(unsigned int minor, unsigned int nr)
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{
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unsigned int end = minor + nr;
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BUG_ON(end > nr_minors);
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spin_lock(&minor_lock);
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for (; minor < end; ++minor)
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__clear_bit(minor, minors);
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spin_unlock(&minor_lock);
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}
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static void blkif_restart_queue_callback(void *arg)
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{
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struct blkfront_info *info = (struct blkfront_info *)arg;
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@ -417,9 +470,14 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
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if ((minor % nr_parts) == 0)
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nr_minors = nr_parts;
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err = xlbd_reserve_minors(minor, nr_minors);
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if (err)
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goto out;
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err = -ENODEV;
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gd = alloc_disk(nr_minors);
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if (gd == NULL)
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goto out;
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goto release;
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offset = minor / nr_parts;
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@ -450,7 +508,7 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
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if (xlvbd_init_blk_queue(gd, sector_size)) {
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del_gendisk(gd);
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goto out;
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goto release;
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}
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info->rq = gd->queue;
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@ -470,6 +528,8 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
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return 0;
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release:
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xlbd_release_minors(minor, nr_minors);
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out:
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return err;
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}
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@ -924,6 +984,7 @@ static void blkfront_connect(struct blkfront_info *info)
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static void blkfront_closing(struct xenbus_device *dev)
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{
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struct blkfront_info *info = dev_get_drvdata(&dev->dev);
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unsigned int minor, nr_minors;
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unsigned long flags;
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dev_dbg(&dev->dev, "blkfront_closing: %s removed\n", dev->nodename);
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@ -946,7 +1007,10 @@ static void blkfront_closing(struct xenbus_device *dev)
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blk_cleanup_queue(info->rq);
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info->rq = NULL;
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minor = info->gd->first_minor;
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nr_minors = info->gd->minors;
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del_gendisk(info->gd);
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xlbd_release_minors(minor, nr_minors);
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out:
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xenbus_frontend_closed(dev);
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@ -1004,7 +1068,10 @@ static int blkfront_remove(struct xenbus_device *dev)
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blkif_free(info, 0);
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kfree(info);
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if(info->users == 0)
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kfree(info);
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else
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info->is_ready = -1;
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return 0;
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}
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@ -1013,18 +1080,22 @@ static int blkfront_is_ready(struct xenbus_device *dev)
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{
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struct blkfront_info *info = dev_get_drvdata(&dev->dev);
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return info->is_ready;
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return info->is_ready > 0;
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}
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static int blkif_open(struct block_device *bdev, fmode_t mode)
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{
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struct blkfront_info *info = bdev->bd_disk->private_data;
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int ret = 0;
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lock_kernel();
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info->users++;
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if (info->is_ready < 0)
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ret = -ENODEV;
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else
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info->users++;
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unlock_kernel();
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return 0;
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return ret;
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}
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static int blkif_release(struct gendisk *disk, fmode_t mode)
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@ -1039,7 +1110,10 @@ static int blkif_release(struct gendisk *disk, fmode_t mode)
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struct xenbus_device *dev = info->xbdev;
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enum xenbus_state state = xenbus_read_driver_state(dev->otherend);
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if (state == XenbusStateClosing && info->is_ready)
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if(info->is_ready < 0) {
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blkfront_closing(dev);
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kfree(info);
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} else if (state == XenbusStateClosing && info->is_ready)
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blkfront_closing(dev);
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}
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unlock_kernel();
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